systemdのログを見てもmysqldが勝手に落ちたことしか分からないので、その原因を知るために、mysqldのログを調べてみた。

驚愕の事実が判明（´Д｀；）

なんかInnoDBエンジンが存在しないから終了したぽい。

なんだよそれ（´Д｀；）

2022-03-08 3:43:13 0 [Note] InnoDB: Using Linux native AIO
2022-03-08 3:43:13 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2022-03-08 3:43:13 0 [Note] InnoDB: Uses event mutexes
2022-03-08 3:43:13 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2022-03-08 3:43:13 0 [Note] InnoDB: Number of pools: 1
2022-03-08 3:43:13 0 [Note] InnoDB: Using SSE2 crc32 instructions
2022-03-08 3:43:13 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instance
s = 1, chunk size = 128M
2022-03-08 3:43:13 0 [Note] InnoDB: Completed initialization of buffer pool
2022-03-08 3:43:13 0 [Note] InnoDB: If the mysqld execution user is authorized, page clea
ner thread priority can be changed. See the man page of setpriority().
2022-03-08 3:43:13 0 [ERROR] InnoDB: Invalid flags 0x4800 in ./ibdata1
2022-03-08 3:43:13 0 [ERROR] InnoDB: Plugin initialization aborted with error Data struct
ure corruption
2022-03-08 3:43:14 0 [Note] InnoDB: Starting shutdown...
2022-03-08 3:43:14 0 [ERROR] Plugin 'InnoDB' init function returned error.
2022-03-08 3:43:14 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2022-03-08 3:43:14 0 [Note] Plugin 'FEEDBACK' is disabled.
2022-03-08 3:43:14 0 [ERROR] Could not open mysql.plugin table. Some plugins may be not l
oaded
2022-03-08 3:43:14 0 [ERROR] Unknown/unsupported storage engine: InnoDB
2022-03-08 3:43:14 0 [ERROR] Aborting